142 Transactions of the Society . 



These forms are represented by Cryptobranclms, in the Miocene 

 of Switzerland, and by the gigantic salamander of Cliina and Japan, 

 now living. 



The tail-less Batkachia, Frogs and Toads, do not make their 

 appearance until Tertiary times. 



All these forms appear to have undergone regular metamorphoses 

 in the young state after leaving the egg. Some of those in the 

 Coal Period, and especially in the Permian, attained to a very large 

 size, and had thick bony plates covering the head. The head varies 

 in form from a broadly semicircular shape in Branchiosaurus,, 

 to a more elongated form in Loxomma and Archegosaurus ; the 

 skull in Mastodonsaurus giganteus, from the Keuper of Wiirtem- 

 berg, measured a yard in length and was broad in proportion. 



Like their modern representatives at the present day, the 

 Amphibia were all of aquatic habits, although air-breathing in the 

 adult ; but they were also capable of progression upon the land — - 

 they represent, therefore, the first terrestrial vertebrates. 



Eepresentatives of both the tailed and tail-less forms, the Newts 

 and Salamanders, and the Progs and Toads, still survive, although 

 greatly reduced in .size. 



The skeleton in the Amphibia presents a combination of cha- 

 racters intermediate between the lowest Mammals and certain 

 of the Anomodont reptiles. 



EEPTILIA. — Of the extinct forms of Eeptiles, the Anomo- 

 dontia are certainly the most remarkable, as they are among the 

 most recent discoveries of geological science. They derive their 

 name from the varied modification of their dentition, so unusual 

 a character among Eeptiles, in which the teeth are, most generally, 

 all of one pattern and size. They were all land animals, with 

 limbs adapted to habitually support the body ; some were of very 

 massive build, others were of much more light and agile form. 



One of the most striking of the former of these is the Paria- 

 saurus Bainii, from the Trias formation of Cape Colony : the teeth 

 are close set, and fused with the bone ; they resemble those of the 

 Iguanodon in being worn down on their summits, as if applied to 

 the mastication of vegetable food ; fifteen or sixteen are closely set 

 on each side of both the upper and lower jaws ; they are very 

 uniform in character, there being no means by which to separate- 

 the incisors or canines from the premolars or molars ; the palate 

 also bears several rows of small teeth ; the entire animal measures 

 fully nine feet in length, and its skull and jaws closely resemble 

 those of the short-headed Labyrinthodont Batrachia ; while the 

 surface of the skull was completely covered by a bony roof 

 sculptured on the surface, like the cranial plates in many 

 Labyrinthodonts and Crocodilia. 



One of the most strange Ehynchocephalian reptiles is the 

 Dimetrodon incisivus from the Permian of Texas, remarkable for 



